Long timescale dynamics of spin textures in a degenerate F=1 $^{87}$ Rb spinor Bose gas

TL;DR

This study explores the long-term evolution of spin textures in a degenerate F=1 Rb-87 spinor Bose gas, revealing how quadratic Zeeman shifts influence domain formation, magnetic anisotropy, and equilibration timescales.

Contribution

It provides experimental insights into the dynamics and equilibration processes of spin textures in a ferromagnetic spinor Bose-Einstein condensate, highlighting the dependence on quadratic Zeeman shifts.

Findings

Large spin domains form at small |q| values.

Equilibration depends strongly on quadratic Zeeman shift.

The system's behavior aligns with mean-field phase predictions.

Abstract

We investigate the long-term dynamics of spin textures prepared by cooling unmagnetized spinor gases of F=1 $^{87}$Rb to quantum degeneracy, observing domain coarsening and a strong dependence of the equilibration dynamics on the quadratic Zeeman shift $q$. For small values of $|q|$, the textures arrive at a configuration independent of the initial spin-state composition, characterized by large length-scale spin domains, and the establishment of easy-axis (negative $q$) or easy-plane (positive $q$) magnetic anisotropy. For larger $|q|$, equilibration is delayed as the spin-state composition of the degenerate spinor gas remains close to its initial value. These observations support the mean-field equilibrium phase diagram predicted for a ferromagnetic spinor Bose-Einstein condensate, but also illustrate that equilibration is achieved under a narrow range of experimental settings, making the F=1 $^{87}$Rb gas more suitable for studies of nonequilibrium quantum dynamics.